Capacitance-based Biosensors for Continuous Monitoring of Glucose

Self-monitoring of blood glucose has become an §important and critical tool for effective management §of patients with diabetes. This book describes §multiple MEMS (Microelectromechanical systems) §sensor architectures that can continuously measure, §in real time, the concentration of glucose in a §solution. The devices incorporate a glucose-§sensitive hydrogel membrane, which swells reversibly §in the presence of a glucose containing solution. §The MEMS architecture transforms the resultant §swelling of the hydrogel membrane into the §displacement of a capacitor plate. Signal §transduction arises directly from motion of one §capacitor plate with respect to the other fixed §plate, resulting in a change in capacitance. Hence §the presence or variation in the concentration of §glucose can be observed as a change in capacitance §of the device. In order to develop the continuous §monitoring glucose sensor, various performance §aspects, like the optimal hydrogel recipe as well as §the repeatability of the hydrogel swelling response §and the development of an efficient microfabrication §scheme to manufacture the sensor, have been §researched extensively.